Clinical Scenario

Matt Black, one of your beef clients, purchases over 400 weaned suckler calves in the autumn and rears them through to finishing weight. Despite his best efforts to prevent the disease, pneumonia remains a significant problem on his unit. Historically he has used an antibiotic containing tilmicosin to treat these animals; however recent safety concerns surrounding its use have made this impossible. He has tried a number of other antibiotics and has not been happy with any of them because he found he had to re-treat a lot of animals (something he did not have to do with tilmicosin). At a recent beef expo event he was talking to one of the large pharmaceutical companies about a new antibiotic containing tulathromycin. He asks you whether you think the new antibiotic will be similar to tilmicosin in the number of re-treatments he has to give...

3-Part Question (PICO)

In [beef cattle with pneumonia] does [the administration of tulathromycin compared to tilmicosin] [reduce the number of times animals need to be retreated]?

Search Strategy and Summary of Evidence

Search Strategy

MEDLINE(R) In-Process & Other Non-Indexed Citations and MEDLINE(R) 1946 to Present using the OVID interface

(calf.mp. OR calves.mp. OR cattle.mp. OR bovine.mp. OR bovines.mp. OR bos.mp. OR exp Cattle/)

Total relevant papers

2 relevant papers from both MEDLINE and CAB Abstracts

Comments

The studies relevant to our question which appear in the two reviews are similar as the searching strategy used was almost identical. However, the data were synthesised differently, so both have been included in this BET as they both contribute information regarding the 3 part (PICO) question of interest.

Key Results:

The direct estimate of the log-odds ratio comparing tilmicosin to tulathromycin was -0.67 with a standard deviation of 0.24, therefore tulathromycin was associated with an approximate 30% reduction in the risk of re-treatment

The risk ratio of re-treatment required for tilmicosin when compared to tulathromycin was 1.87 (95% Confidence interval 1.23-2.74), suggesting re-treatment almost twice as likely when using tilmicosin

Study Weaknesses:

There was no protocol developed prior to the review though a previously published review (O'Connor et al. 2013) was used in place of a protocol for this update.

A list of included and excluded studies were not provided, though some of this information is in the references and the original review.

The characteristics of the individual studies included in the review are not provided but the eligibility criteria is fairly tight so variation amongst studies should be limited. Some detail of the 5 new studies included in this review were given.

The review was limited to studies conducted in North American feedlots.

Studies considered in the review are potentially biased.

The conflict of interest of the authors of this review are given but not those of all the studies included in the review (as per AMSTAR; see details below)

Attachment:

Wellman and O’Connor (2007) USA

Meta-analysis of treatment of cattle with bovine respiratory disease with tulathromycin

Patient group:

Cattle with bovine respiratory disease (BRD)

Study Type:

Systematic review with meta-analysis

Outcomes:

Relative risk of number of re-treatments

Average daily gain (ADG)

Mortality

Key Results:

Nine trials were found that examined re-treatment of tulathromycin vs tilmicosin.

Meta-analysis of nine trials showed that tulathromycin was associated with approximately 50% reduction in the risk of re-treatment (relative risk of re-treatment for tulathromycin vs tilmicosin was 0.56; 95% confidence intervals 0.48-0.64).

Summary of effect for ADG or mortality was not possible as only one study presented precision estimates for these outcomes - that paper detected no difference in ADG or mortality between tulathromycin vs tilmicosin.

Study Weaknesses:

The review was limited to studies conducted in North American feedlots.

Studies considered in the review are potentially biased.

There was no attempt to retrieve missing data.

Tulathromycin was not used as a search term in the literature search.

Attachment:

Comments

This is an updated version of the BET originally published in December 2013 and authored by Dr Martin Downes and Dr Kathryn Wareham.

The original BET included Wellman and O'Connor (2007), and the critique of this systematic review has not been altered. The review by O'Connor et al. (2016) has been indexed since the original BET was published so has been included. O'Connor et al. (2016) is an updated review from a previous manuscript published in 2013, and the reference for this is given below. The bottom line of the BET has not been altered.

Both systematic reviews are well designed and reported, enabling a straight forward critique of the methods using the AMSTAR tool https://amstar.ca/.

It must be noted that a high proportion of the trials used in the systematic reviews have been provided by the pharmaceutical companies marketing tulathromycin.

Bottom line

In beef cattle with pneumonia the administration of tulathromycin is associated with a decreased risk of re-treatment when compared with tilmicosin.

Disclaimer

The BETs on this website are a summary of the evidence found on a topic and are not clinical guidelines. It
is the responsibility of the individual veterinary surgeon to ensure appropriate decisions are made based on
the specific circumstances of patients under their care, taking into account other factors such as local
licensing regulations. Read small print